IBS vs ides, What's the Difference?

Which to use

“IBS” is an adjective and “ides” is a noun - they look or sound alike but fill different roles in a sentence.

#32,851
“IBS” frequency rank: #44,856
“ides” frequency rank: 77707
confusion score

Side-by-Side Comparison

Feature	IBS	ides
Definition	Initialism of identical by state.	The notional full-moon day of a Roman month, occurring on the 15th day of the four original 31-day months (March, May, Quintilis or July, and October) and on the 13th day of all other months.

Where the spellings diverge

Shared letters are muted; the letters that actually set IBS and ides apart are highlighted. They share 2 letters in sequence, which is exactly why the eye skips the difference.

3 ch

IBS

4 ch

ides

Spelling & Dictionary Insight

These two trip readers on the page rather than in the ear: IBS is /aɪ.biːˈɛs/ while ides is /aɪdz/. Spoken aloud the problem disappears. In writing it persists, because they differ by 1 letter(s) in length, and the parts of speech differ too (adjective vs noun), which is usually the fastest check. Our composite confusion score for this pair is 77707, derived from the frequency rank of both members and their visual similarity.

IBS is recorded at frequency rank #32,851, classified as anadj, pronounced /aɪ.biːˈɛs/. ides is at rank #44,856, tagged as anoun, pronounced /aɪdz/.

Glosses for this pair are partially populated in our dataset, but the full side-by-side definitions above should still guide you to the right choice.

With a confusion score of 77707, this pair ranks #26,518 of 530,003 scored English confusable pairs - among the most confusable pairs.

Orthographic DNA of IBS vs ides

Shared letters: is. Private to "IBS": b. Private to "ides": de.

"IBS" · 3 letters · shape VCC · "ides" · 4 letters · shape VCVC

Known mistypes of this pair

ides ← iddes · idess · idse · ieds

Frequency comparison

IBS#32,851

ides#44,856

Source: FrequencyWords open word-frequency list

Frequently Asked Questions

Can "IBS" and "ides" be used interchangeably?

No - they are not even the same part of speech. "IBS" is an adjective and "ides" a noun, so a sentence built for one is usually ungrammatical with the other.

Which is more common, "IBS" or "ides"?

"IBS" is the more common of the two: it sits at frequency rank #32,851 in our English list, against #44,856 for "ides". The two are close in frequency, so neither is a safe default; check the meaning rather than guessing.

Remembering IBS vs ides

The fastest way to pick the right one every time.

Check the role first: if you need an adjective, it's “IBS”; for a noun, it's “ides”.
See each word in full, definition, IPA, etymology and its other confusables. Full “IBS” entry
Browse more pairs most likely to be confused. Most confusable